Yes, but slavery is abolished for centuries in Braavos (well it never existed but nvm) but Volantis is different, look at what happened to countries that tried to adapt from socialism to capiralism over night, or countries that from dictatorship suddenly rushed into "democracy". These things take time and when that time is too short chaos eurupts.
You may be right here and this is likely option, but certainly not the only one. We do not know much about her, in fact we know very little about her and almost nothing about her character so we can not say how she feels about that. We only have what she said to knight she clearly doesnt like or trust and kinslaying kingalaying dwarf that half of the world wants to kill.
Half of tiger faction follow Rhllor and they still wish war and prefer slavery over saviour. And she may feel revenge but she should know that she will suffer, too. Again we do not know enough about her to discuss this.
Well, maybe, but Sam almost died for smaller problem in Braavos, it is weird to reqard someone that almost killed your guest, costomer or whatever under your roof. Tyrion has a reason to be nice to her because of his situation, it was kinda expected. I thought I read that at one moment but I could not find it tonight when I was searching those chapters (Tyrion and Jorah insisting), but even if this was true widow likely read them well and she could somehow manipulate them to invite her.
I actually dont think it is the ship, but if it is Penny seems most plausible to me, I do not know who is seneschal, but I would argue it is Illyrio or maybe even Marwyn. I would also argue that her listening to Quaithe is very wrong but this is story for another time.

So you think she has no slaves at all and she can without any problem continue bussoness as usual if slavery is abolished? Lets be generous and assume it will happen, but people around her arent gonna be that lucky, Volantis will eurupt into chaos if slavery is abolished and she, woman who lives from counting how big risk is and what reward can she get from risking, just doesnt seem like someone who would think everything will be great and people will be happy and everyone will live long and peaceful live with husband/wife and many many healthy children.
I do not say if there is so ething more ti her story, all I am saying is that some thing are not clear there.
But why would she give her wine and clothes? She tried to kill a man under her roof, see how it went for Sam for far lesser form of agression. Why would she get to drink and clothes for free?
What makes you think she didnt do some of those things? We have absolutely no proof that she isnt in slaver coalition. I did not claim she is suppoused to kill Daenerys, only to harm her or her cause somehow since it is likely she will eventually come in her proximity, and if not... well she lost a cup of wine, some clothes and a ship ticket.
Those FM thoeries always crack me up, when I hear someone is FM I usually think about one minute about it and dozen reasons that make it impossible come on my mind.

I am just saying that maybe she was on a mission that has goal to harm Daenerys.Widow has no reason to back her and Penny has no reason to be on that ship. I do not know what is happening and I do not have idea, but something is suspicious there.

Lets assume it is the ship.
We have excluded Tyrion and Moqorro.
Jorah would be kinda pointless since she knows not to trust him.
Who else do we have that was on ship and that very likely might be near Daenerys in future? Penny.
What I never understood is why she was on Selaesori Qhoran in the first place? I mean widow of waterfront sent her but why? Does she need to spy on Daenerys? Kill her? Why would widow like slavery to be abolished, she is slaver herself (yes, she might feel so e sympathy for slaves but that doesnt change the fact that her present and future depend on slaves).

Arianne wont marry him, it would be idiotic and sabotage their alliance.
He will get most of the Reach (Tarly, Rowan, Hightower)and defeat Mace and Lannisters.
Will sit there for a while, play war with Euron, Daenerys will come, accuse him of being mummers dragon (and this is why I like idea of him being real deal, it would be much more tragic and heartbreaking) and kill him. I just hope JonCon dies somewhere between Aegon is crowned and killed.

Agreed, ohhhh that would be soo awesome to see him witness battle.
Yes, Theon will have to claim Pyke via force. There are a lot of options such as, Stannis wins and Theon finishes him with Manderly fleet (not likely but this chapter was more than unlikely to predict), Ironborn betray Euron, they get crushed by Redwynes or maybe even Hightowers,...
I dont know who will rule at the end but Euron will fall eventually.
I just dont see Theon winning Kingsmoot even if Euron would ever accept one. After 3 minutes of taunting he would start to call himself Reek and Ironborn dont want Reek as a King.

I dont have enough time to go trough all comments and see if anyone else wrote this, but here is what I find interesting:
SE fell in a day?? Mace didnt do it with larger army, so there must be some kind of a deal, but what deal? Between defenders and Aegon or Stannis and Aegon?
Arianne will dislike Aegon but try to seduce him in order to be Queen, or more important not to see Quentyn becoming her King. And this may lead to downfall of Aegon.
There were multiple hints that Aegon is a Blakfyre.

What if both Arya and Sansa take the role of LS? Arya will go to Riverlands so she can kill Freys and Lannisters and Sansa can order Brienne in the start of season to kill Jaime to prove her loyalty, why else would Brienne abandon Sansa and leave south?